The 2,000-year-old basilica was “once the beating heart of Roman London,” the Museum of London Archaeology said.

Archaeologists exploring the site of a planned 32-story office tower announced Thursday that they have unearthed the remains of a Roman basilica that once stood at the heart of the city known as Londinium.

Experts are surprised at how much of the basilica, or town hall, survived. The ancient building was part of Roman London’s political and commercial center.

An office building from the 1930s in the heart of London was about to be demolished and redeveloped by its owners — until archaeologists unearthed remnants of the city’s first Roman basilica in the basement.

While exploring the site of a 32-story planned skyscraper in London, archaeologists unearthed the ruins of a nearly 2,000-year-old Roman basilica.